The cacti of the United States and Canada

exhaustive treatise of the species and varieties of cacti native to North America north of Mexico, including chapters on structure, biochemistry, physiology, classification, study techniques, biogeography, habitats, human uses, and conservation; copious line drawings and photographs of every taxon; and complete keys, descriptions, and distribution maps. Some of the taxonomy is outdated, and there appear to be occasional lapses in taxonomic judgment. Of great interest to lay readers and professionals.